57 – Interaction between Rheumatoid Arthritis and Infections

Publisher Summary Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease characterized by a symmetric inflammation and destruction of joints. Despite of large efforts and technology, the etiology of RA remains elusive, although it appears that genetic, infectious, environmental, and hormonal factors are all involved in complex interrelated ways. One of the most exciting areas of investigation is the application of Polymerase Chain Reaction (PCR). This technique is useful to the detection of bacterial and viral DNA in patients with RA. With PCR technique, foreign antigens of bacteria, virus, and superantigens can be found in the synovial fluid. In addition, the lymphocytes from synovial fluid can develop a local immune response stimulated by microorganisms such as Proteus mirabilis and Epstein-Barr virus. These lymphocyte responses were higher with these microorganisms than with other stimuli. Those data suggest an immune-infectious cause for RA. However, the difficulty of separating pathogens from contaminants has hampered these studies. On the other hand, the presence of foreign antigens is not specific for RA. Therefore, the role of these organisms in initiating and perpetuating inflammation in RA remains unknown; however, it continues to be actively investigated. This chapter provides an update on the various mechanisms in which infectious agents may play a role as inciting or perpetuating factors in the pathogenesis of RA.